Block #6,784,927

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 4/5/2026, 10:52:00 PM · Difficulty 10.9809 · 227 confirmations

2CC

Cunningham Chain of the Second Kind

A sequence where each prime is double the previous prime minus one.

Block Header

Block Hash

96f4b9abc55edda3604c9d7aac1992024a9c928e64d665ed341d7024e748102c

View on Chainz ↗

Height

#6,784,927

Difficulty

10.980862

Transactions

Size

191 B

Version

536870912

Bits

0afb19c7

Nonce

554,361,278

Timestamp

4/5/2026, 10:52:00 PM

Confirmations

227

Merkle Root

88fff9d14831d6e12bc3f816ec4093487faceb6baed28dcae38d5f55e3893d48

Transactions (1)

Coinbase88fff9d14831d6…8d5f55e3893d48

1 in → 1 out8.1790 XPM101 B

AMrLYUQN…jwjifxiz

Prime Chain Origin

This is the prime chain origin stored in the block header. It is a composite number (not prime itself) — it equals the first prime in the chain multiplied by a primorial. The origin anchors the entire chain to this specific block.

1.249 × 10⁹⁵(96-digit number)

12491079401457636190…94177511114191775041

Discovered Prime Numbers

p_k = 2^k × origin + 1

These are the actual prime numbers discovered by this block, computed using the verified Primecoin formula. Each number has been independently confirmed to pass the Fermat primality test. Use the FactorDB links to verify any number independently.

origin + 1

1.249 × 10⁹⁵(96-digit number)

12491079401457636190…94177511114191775041

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^1 × origin + 1

2.498 × 10⁹⁵(96-digit number)

24982158802915272381…88355022228383550081

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^2 × origin + 1

4.996 × 10⁹⁵(96-digit number)

49964317605830544763…76710044456767100161

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^3 × origin + 1

9.992 × 10⁹⁵(96-digit number)

99928635211661089527…53420088913534200321

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^4 × origin + 1

1.998 × 10⁹⁶(97-digit number)

19985727042332217905…06840177827068400641

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^5 × origin + 1

3.997 × 10⁹⁶(97-digit number)

39971454084664435810…13680355654136801281

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^6 × origin + 1

7.994 × 10⁹⁶(97-digit number)

79942908169328871621…27360711308273602561

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^7 × origin + 1

1.598 × 10⁹⁷(98-digit number)

15988581633865774324…54721422616547205121

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^8 × origin + 1

3.197 × 10⁹⁷(98-digit number)

31977163267731548648…09442845233094410241

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^9 × origin + 1

6.395 × 10⁹⁷(98-digit number)

63954326535463097297…18885690466188820481

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^10 × origin + 1

1.279 × 10⁹⁸(99-digit number)

12790865307092619459…37771380932377640961

Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 consecutive prime numbers forming a Cunningham Chain of the Second Kind. The prime chain origin — the large number shown above — anchors the chain and is divisible by a primorial (the product of small primes), cryptographically tying these prime numbers to this specific block.

★★★☆☆

Rarity

RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

How Primecoin's Proof-of-Work Constructs These Primes

Primecoin stores a value called the prime chain origin in each block. The miner found a large integer such that when divided by a primorial (the product of small primes: 2 × 3 × 5 × 7 × …), the result is the first prime in the chain. The origin is deliberately divisible by this primorial — that divisibility is part of the proof.

Prime Chain Origin = First Prime × Primorial (2·3·5·7·11·…)

Source: Primecoin prime.cpp — CheckPrimeProofOfWork()

This is why the origin has many small prime factors — those factors are the primorial divisor. The chain then extends from the first prime using the 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …

Cross-reference on Chainz Explorer